Structural reticulated webs or honeycombs and curtain wall panels made from same



Oct. 27, 1959 B. M. RANDALL ET AL 2,910,396

STRUCTURAL RETICULATED WEBS OR HONEYCOMBS AND CURTAIN WALL PANELS MADE FROM SAME 2 Sheets-Sheet 1 Filed Nov. 12. 1952 1959 B. M. RANDALL ET AL 2,910,396

STRUCTURAL RETICULATED WEJBS 0R HONEYCOMBS AND CURTAIN WALL PANELS MADE FROM SAME Filed Nov. 12, 1952 2 Sheets-Sheet 2 2,9 l 0,3 96 Patented Oct. 27, 1959 STRUCTURAL RETICULATED WEBS OR HONEY- COMBS AND CURTAIN WALL PANELSMADE FROM SAME Boardman M. Randall, Portsmouth, and Ralph S. Frobisher, Newcastle, N.H., assiguors, by mesne assignments, to The Bettinger Corporation, a corporation of Massachusetts Application November 12, 1952, Serial No. 320,052

9 Claims. (Cl. 154-453) 'This invention relates to improvements in reticulated webs or honeycombs of the general type suitable for use as an insulating medium in structural panels. More particularly, the invention provides such reticulated webs or honeycombs which are highly fire and flame resistant and which have superior strength for resisting stresses and strains, as compared with prior comparable web structures. Actually, our improved reticulated webs or honey- =combs may be faced on one or both sides with conven- "tional panel-facing elements or skins to' produce structural panels of exceptional strength and fire and flame resistance, or may be utilized in various ways as accoustical and/ or light-reflecting media interiorly of buildings. Hence, it should be understood that the herein described embodiments of the invention in connection with panel- :facing elements or skins are merely illustrative of parti- -'cular embodiments, and that the improved webs or honeycombs may be variously utilized with or without facing elements on either or both sides of the webs or honeycombs.

Reticulated webs or honeycombs of the general type to which the invention relates have been made heretofore of treated paper and have constituted cores intervening beitween panel-facing elements secured to opposite sides of the webs or honeycombs. Heretofore, however, the ;.paper stock of the webs or honeycombs has been impreg- :nated with resinous substances to impart needed stiffness :and strength to the cores, and the resinous substances ,have made the webs or honeycombs suitably moisture L-resistant. But, the prior resin-impregnated paper cores rare highly inflammable, and the prior bonding agents for .securing the facing elements to the cores, required to be ithe same as or compatible with the resinous substance with which the cores are impregnated, have not been capable of withstanding flame. Also, the use of resinous substances and adhesives, besides being relatively expensive, creates problems when the resin-impregnated cores must be bonded to'various types of facing elements, such :as, for example, facing elements of metal, commercial asbestos-cement board, and commercial gypsum board.

It is among the objects of our present invention to provide a relatively inexpensive reticulated paper web or honeycomb structure which can successfully and effectively withstand direct contact with flame, which may be moisture resistant, and which readily and effectively may 'be combined with any of the conventional panel-facing elements or skins to provide a relatively inexpensive lightweight structural panel having superior qualities of rigidity and strength as compared with prior comparable panels, and having the important characteristic of being able to successfully resist the ravages of flame and high ?temperatures.

Another object of the invention is to provide a reticulated paper web or honeycomb structure which is coated with relatively inexpensive cementitious material and which may be effectively bonded to panel-facing elements or skins by a cementitious bonding material which may be the same as'or compatible with the coating material, the said cementitious material having the character that it sets and converts the paper web or honeycomb into a rigid and strong flame-proof structure capable of hear-- ing substantial loads.

A further object of the invention is to provide a reticulated web or honeycomb structure made of paper which is capable of absorbing appreciable amounts of a cementitious material when the web or honeycomb structure is immersed in a suitably fluid supply of the cementitious material, which latter also forms as a relatively hard and strong coating over allsurfaces of the web or honeycomb, whereby the coated web or honeycomb may be exposed interiorly of a building as an accoustical medium and, when the coating is white or a suitably light color, may serve as a light-reflecting medium in connection with the lighting equipment within a building.

Yet another object of the invention is to provide a structural panel having a reticulated web or honeycomb secured to a facing element, or intervening between two facing elements and secured to both, by a cementitious material which also coats all surfaces of the reticulated web or honeycomb, the cementitious material being set to hardness to provide a strong panel which is highly fire and flame resistant.

Still another object of the invention is to provide a structural panel wherein a reticulated web or honeycomb of absorbent sheet material has a cementitious material strongly adhering to all of its surfaces and edges and set to hardness thereon, said cementitious material either filling all cells and voids within the web or honeycomb or adhering as a coating over said surfaces and edges, one

or both sides of the web or honeycomb having means thereon constituting a facing for the panel.

Yet a further object of the invention is to provide a structural panel wherein a reticulated web or honeycomb of absorbent sheet material has a coating of cementitious material covering and strongly adhering to all surfaces and edges of the web or honeycomb, with a substantial body of cementitious material formed as a facing at one side or both sides of the coated web or honeycomb and self-bonded to the cementitious coating over the surfaces and edges of the web or honeycomb.

It is, moreover, our purpose and object generally to improve the structure and effectiveness of structural panels and especially such panels having a reticulated web or honeycomb structure faced, or to be faced, on one or both sides with a panel-facing element or skin.

In the accompanying drawings: V

Fig. l is a perspective view of a fragment of a partially opened reticulated paper web or honeycomb structure which may be coated with cementitious material in accordance with the teachings of our invention;

Fig. 2 is a plan view of the web or honeycomb of Fig. 1 in a fully open state and coated with a cementitious material;

Fig. 3 is a cross-sectional view on line 33 of Fig. 2;

Fig. 4 is an isometric view of a section of a completed structural panel embodying features of the invention, with a portion of one of the facing elements broken away;

Fig. 5 is a cross-sectional view on Line 55 of Fig. 4, on a larger scale;

Fig. 6 is a detail view of a fragment of the panel of Fig. on a still larger scale;

Fig. 7 is a view similar to Fig. 6 but showing our improved coated web or honeycomb structure combined with another variety of facing element;

Fig. 8 is a cross-sectional view through a portion of another modification of the invention wherein the facing elements may be porcelain-'on-metal pans applied to op posite sides of our improved reticulated core;

Fig. 9 is a perspective view of a corner fragment of one of the pans of Fig. 8, showing the interior of the pan roughened, as by sand blasting;

Fig. 10 is a perspective view of a portion of a modified form of reticulated web structure which may be coated with cementitious material to provide a panel core in accordance with the teachings of our invention;

Fig. 11 is a cross-sectional view of a fragment of a modified form of panel wherein the cells and voids within a reticulated web or honeycomb are filled with cementitious material which strongly adheres to the walls of the web or honeycomb, and wherein one side is faced -with a conventional panel-facing element and the other side has cementitious material, similar to that constituting the filler, formed thereon to constitute a panel facing, the support or forming die also being shown;

Fig. 12 is a detail cross-sectional perspective view of a fragment of the web or honeycomb of Fig. 11, notched to permit inter-connection of cementious masses in adjacent cells or voids of the web or honeycomb; and

Fig. 13 is a cross-sectional view of a fragment of another modified form of panel wherein a web or honeycomb coated with cementitious material has a mass of cementitious material formed on one side thereof for constituting a panel facing, which panel facing penetrates into the web for a limited distance for additional strength, and showing the forming support or embossing die.

Referring to the drawings, a fragment of a commercially available variety of a reticulated paper web or honeycomb structure 10 is represented in Fig. 1, in a partially opened state, although it should be understood that the invention is not restricted to any particular material or variety of reticulated web structure so long as it is of a more or less absorbent sheet material organized to provide a multiplicity of relatively large air spaces or cells 12 therein. The reticulated web or honeycomb structure it) of Fig. 1 is available commercially in compacted strips of any desired width, which may be drawn out to provide the partially opened honeycomb structure of Fig. 1 which is shown in fully opened coated condition in Fig. 2.

Heretofore, however, the paper honeycomb structures destined for use in structural panels have employed paper stock impregnated with resinous substances which contribute needed stiffness and strength to the cellular walls of the honeycomb and also render the honeycomb suitably moisture resistant. Such a resin impregnated paper honeycomb structure, when faced with conventional panel-facing elements or skins, has been satisfactorily usable as a structural panel where moisture resistance has been a primary requirement. But these prior panels could be in no practical sense fire and flame resistant, or effectively resistant to high temperatures, because in treating the paper honeycomb structures to provide them with needed stiffness and strength and moisture resistance, they have been rendered highly inflammable, and the required bonding agents for combining the honeycombs and facing elements or skins have been highly inflammable.

Our present invention employs conventional reticulated webs or honeycombs of relatively low cost sheet material which preferably is substantially free of resins and sizing substances, so that the sheet stock is in condition to absorb, or be penetrated by, a fluid cementitious substance, at least to a substantial degree. The honeycomb structure may be immersed in such a fluid cementitious ma- 4. terial to thoroughly coat all exposed surfaces of the honeycomb structure, with the cementitious substance en tering appreciably into the sheet stock for effecting a secure bond between the sheet stock and the coating when the cementitious material sets and ultimately dries.

Paper stock which is substantially free of sizing substances and resins presently is considered to be a preferred sheet material from which to form the reticulated webs or honeycombs for use in our improved structural panels. The mentioned paper honeycomb structure, as represented at if) in Fig. 1, may be purchased with its paper stock free or substantially free of resins and sizing substances, and such a paper honeycomb of suitable width, and of suitable area when fully expanded, has proven to be a highly acceptable reticulated web or honeycomb structure capable of being effectively coated with a cementitious material and effectively combined with any of a variety of panel-facing elements or skins in accordance with teachings of the invention.

Examples of cementitious coating materials suitable for use in producing our improved reticulated webs or honeycombs, and our improved structural panels are Portland cement, gypsum plaster, Keenes cement, and other comparable relatively low cost cementitious materials of the class which may be more particularly described as mineral hydraulic cementitious materials. Portland cement, reduced by addition of water to a suitable consistency, presently is regarded as a preferred cementitious material for coating the reticulated web or honeycomb structures of panels which must be highly moisture resistant as well as highly flame and heat resistant, such as panels which will be exposed to the elements at exterior portions of buildings, for example. Usually, addition of a relatively small amount of an accelerator or a retarder will be advisable, for suitably controlling the setting of the Portland cement. On the other hand, a water and gypsum plaster, of suitable consistency, presently is considered to be a preferred cementitious material for coating the reticulated web or honeycomb structures of panels which are not required to be highly moisture resistant, such as panels for use interiorly of buildings, for example. Here again, an accelerator or retarder may be added to the plaster to suitably control its setting. Either the Portland cement or the gypsum plaster, when coated on the reticulated web or honeycomb structure 10, as at 14 in Figs. 2-8, render the web or honeycomb structure highly heat resistant and substantially flame-proof. When Portland cement is used, the coated structure is also highly moisture resistant. Commercial Magnesite, and silicate of soda combined with calcium carbonate or whiting, are other materials falling within the general class of mineral hydraulic cementitious materials which may be used for coating our reticulated web or honeycomb structures.

The prior comparable structural panels which have employed resin-impregnated paper honeycomb structures between panel-facing elements have, to a considerable extent, been limited as to the varieties of facing elements which could be effectively combined with the honeycomb structures or cores. Problems have been involved to effectively and durably bond the facing elements to certain varieties of conventional panel-facing elements. It is a notable feature and advantage of our coated web or honeycomb structures that they are effectively and durably bondable to any of the conventional varieties of panel-facing elements by means of a bonding material the same as or compatible with the coating material.

Referring to Figs. 4-6, the facing elements 16, 16 represent sections of commercial plaster-board, each of the facing elements or boards being of a commercial variety which is surfaced on both sides with paper 16'. The cementitious coating 14 on the Web or honeycomb structure 10 may be either gypsumplaster, Portland cement, or the like. Assuming that it is gypsum plaster, each facing element 16 will be coated at 20 on one side with gypsum plaster, or a cementitious substance compatible therewith, preliminary to combining of the elements 16 with the coated honeycomb. One of the facing elements 16, coated on one side as at 20, may be arranged in a suitable box or form with its coated side up, and the web or honeycomb structure, in its coated condition of Fig. 2 and while its coating continues in a plastic condition, is arranged on the element 16 in the box or form with the walls of the honeycomb perpendicular to the element 16. If the honeycomb is not fully spread or opened it may be fully opened as it is arranged on element 16, after which it is pressed against element 16, so that their plaster coatings merge as in Fig. 6. The second facing element 16 with its plaster coating on its under side, next is arranged on and pressed against the web or honeycomb within the box or form. The assembled panels may be stacked one upon another and be left to dry in atmosphere, or they may be subjected, according to known procedures, to conditions for hastening a complete curing and drying of the panels. The complete panels are exceptionally well suited for interior portions of buildings and for other uses where it may be important to have flame-proof and highly fire and heat resistant panelling which also provides great strength and rigidity at relatively low cost.

Fig. 7 illustrates a panel structure which is faced on at least one side with a commercially available variety of asbestos cement board 26. In this case the reticulated paper web or honeycomb 10 is coated with Portland cement 28 and that surface 27 of the board 26 which is toward the coated web or honeycomb is coated with Portland cement, or a mineral hydraulic cementitious substance compatible with Portland cement. The other side of the reticulated web 10 of the panel of Fig. 7

may be similarly faced with an asbestos cement board 26, or this other side may be faced with a gypsum plaster board similar to the plaster boards 16 of Figs. 4-6, or with some other facing element, such as a porcelain enameled steel facing element. For example,

a panel may be assembled having one side faced with asbestos cement board, for exposure to the elements exteriorly of a building, and having its other side faced with gypsum plaster board, for inside exposure where moisture resistance is not of great consequence. The Portland cement provides an effective durable bond to both an asbestos cement board and a gypsum plaster board, and the resulting panel will be flame-proof and highly resistant to heat, and will have great strength, whether or not only one of its faces is of asbestos cement board. The face which is of asbestos cement board, as well as the coated core, will be highly moisture resistant.

The panel represented in Fig. 8 has a porcelain enameled steel pan type of facing elements 30 combined with a coated reticulated web or honeycomb 10 whose coating material 32 may be Portland cement, gypsum plaster, or a comparable mineral hydraulic cementitious material.

Panels to be exposed exteriorly to the elements preferably should have cores coated with Portland cement and bonded to the facing elements by Portland cement. Gypsum plaster-coated and bonded cores maybe employed when the panels are not required to be highly moisture resistant.

However, it should be understood that one of the facing elements of Fig. 8 might be replaced by an asbestos cement board similar to the board 28 of Fig. 7, or a gypsum plaster board similar to the boards 16 of Figs. 4-6, or by some other facing element.

The porcelain enameled steel facing elements 30 are required to have their interior surfaces porous, or roughened to enable the cementitious coating and bonding material to acquire a secure gripthereon. The

stippling at 34 in Fig. 9 represents such porous or roughened surfaces to which either Portland cement or gypsum plaster will effectively bond.. The selection as betweenPortland cement or gypsum plaster will depend upon whether one facing element is an asbestos cement board or a gypsum plaster board, and the requirements as regards moisture resistance in the finished panel.

Other varieties of reticulated paper webs or honeycombs than that of Fig. 1 may be employed in practicing our invention. For example, an egg-crate type of reticulated paper web as represented in Fig. 10 may be coated with a mineral hydraulic cementitious material, as described in connection with the honeycomb structure 10, and be combined with facing elements or skins to produce panels similar to the panels of Fig. 48.

Referring now to Fig. 11, the illustrated reticulated web or honeycomb 10 may be the'absorbent paper structure of Fig. 1 but, in Fig. 11, the paper is not coated but its cells or voids are entirely filled with mineral hydraulic cementitious material 36 which may be asbestos cement but which, preferably, will 'be gypsum plaster. Inasmuch as the reticulated paper web is absorbent, substantial amounts of the cementitious material, when in a suitably fluid state, penetrate into the paper of the web. Hence, when the cementitious material has set, a relatively strong bond exists between the cementitious material and the paper web 10. This filled reticulated web may have a conventional variety of facing element or skin applied to one or both sides thereof, or the facing at one or both sides may be formed on the web during the filling procedure. In Fig. 11, a conventional paperfaced commercial plaster board facing element 16, similar to those employed in the panels of Figs. 4-6, is applied to the upper side of the panel of Fig. 11. Preferably this facing element 16 will be coated on its under side with the same cementitious material which is used to fill the web, or a cementitious material compatible therewith, so that the coating material and the.

filler material merge to provide an effective and strong bond. The facing element 16 may be applied while the web-filler is in a more or less fluid state, or, if the filler has become set, the end portions may be coated with the bonding coating to attain an effective bond between the web and the facing element. If desired, the web may have notches or grooves 38 in its cell walls (see Fig. 12) whereby the cementitious material filling the web flows into the notches to effect locking and strengthening interconnections between the filler masses in adjacent cells of the web.

Obviously, both sides of the filled web or honeycomb of Fig. 11 may be similarly faced.

However, as shown in Fig. 11, the lower side of the filled web or honeycomb 10 has a facing of mineral hydraulic cementitious material formed thereon as a result of inserting the web or honeycomb into a suitable fluid body of the cementitious material supported in a manner whereby the cementitious material which fills the cells of the web and the cementitious material which forms the lower facing on the web are continuous cementitious bodies. The under support 44 for the cementitious material may be plane or may be variously formed or embossed to provide any of various surface effects at the outer surface of the lower facing of the panel. The web may be filled at the time the lower facing of cementitious material is being formed thereon, or the filler cementitious material may be set or partially set within the web when the web is inserted into the facing cementitious material. In either case, the filler masses and the facing mass join to provide continuity of cementitious material within the cells and at the lower 7 face of the panel.

facingformed thereon by inserting one side of the coated Web or honeycomb a little into a fluid supply 'of mineral hydraulic cementitious material 48 whereby the cementitious material 48 forms a facing on the panel substantially integral with the coating on the web or honeycomb. The material 48 enters a little into the cells, and a strong bond is effected. In Fig. 13, the support 44 has an embossed or otherwise decorative top surface whereby the surface of the facing formed on web 10 will be correspondingly embossed.

Obviously, one side of a panel may be faced as illustrated in Fig. 13, and the other side may be similarly faced or left without any facing. Or one side may be faced as in Fig. 13 and the other side may have a conventional facing element thereon, such as a plaster board facing element 16 as shown in Figs. 4-6 and 11. Also, it will be obvious that the formed facing of Fig. 13 may have a plane outer surface or an embossed outer surface.

In any case where coated webs or honeycombs are faced on both sides to produce a panel, interior crossventilation for such panels may be provided, if desired, by preliminarily punching relatively large holes through the cell walls of the paper web or honeycomb, of size large enough so that they do not become closed as a result of coating of the web. The punching may be accomplished while the walls of the cells of the paper Web are closed fiat against each other. Such holes are shown at 50 in Fig. 13, with their edges coated with the cemcnti-,

tious coating material, the same as the other edges of the web or honeycomb.

With the foregoing and other objects in view, the invention resides in the novel arrangement and combination of parts and in the details of construction and process of manufacture herein described and claimed, it being understood that changes in the precise embodiment of the invention herein described may be made within the scope of what is claimed without departing from the spirit of the invention. It will be further understood that our invention is susceptible of embodiment in many and various forms, some of which are illustrated in the accompanying drawing, and that the structural details or particular procedures herein set forth may be varied to suit particular purposes and still remain within our inventive concept.

We claim as our invention:

1. A reticulated web of paper having wall portions defining cellular voids open at opposite sides of the Web, and highly flame-resistant mineral hydraulic cemtitious material covering substantially all surfaces and edges of the reticulated web and providing a relatively rigid coating having substantial thickness over substantially all surfaces and edges of the reticulated web, thereby to provide a relatively rigid cellular structure which is substantially proof against heat and flame.

2. A structural panel comprising a reticulated web of paper having wall portions defining cellular voids extending through the said web from one side to the other thereof, a panel-facing element at one side of said web, covering all of said voids, highly flame-resistant mineral hydraulic cementitious material adhered as a substantial coating over all of the surfaces and edges of said web and set thereon as a rigid protective reinforcement of said paper of the web, and similar highly flame-resistant mineral hydraulic cementitious material on said facing element set to rigidity thereon and merged with said webcoating cementitious material to effect a durable highly flame-resistant bond between said facing element and said coated reticulated web thereby to provide a relatively rigid cellular structure.

3. A structure as defined in claim 1, wherein the said reticulated web of paper stock is substantially free of any introduced stiffening agent, and said flame-resistant cementitious material will be appreciably absorbed into said paper.

4. A reticulated web as defined in claim 1, wherein, said cementitious web-coating material is of the nature of ly covered web and constituting a panel facing thereon thereby to provide a relatively rigid cellular structure.

-.6. A reticulated web as defined in claim 1, wherein at least some of'the wall portions defining said cellular voids have openings therethrough and said coating material extends through said openings to form connections between the coating material on opposite sides of the wall portions.

. 7. A stressed skin structural building panel comprising a core and a pair of facing elements, said core being made from a series of undulating layers of sheet material forming a honeycomb, said sheet material being substantially solid and substantially unperforated, the said honeycomb core so formed having walls of equal length and forming separate hexagons bonded together at spaced intervals, the .cross sectional area of said various hexagons forming said core being small so as to impart rigidity and strength to said building panel, said honeycomb core being provided on its non-bonded exposed areas with an after-coating of a mineral hydraulic cementitious material whereby said core will be highly flame-resistant and will have added rigidity, said facing elements being highly fire resistant, said after-coating cementitious material being applied to the inner face of each facing element, and said after-coating on the ends of said core and on the facing elements providing a fire resistant bond between the fire resistant core and the fire resistant facing elements, said building panel being provided with a relatively rigid cellular structure.

8. A light weight stressed skin structural building panel comprising a core and at least one facing element, said core comprising a preformed web in the shape of a honeycomb, said web being substantially solid, the various side portions of said web forming said honeycomb core being of substantially equal length and forming separate hexagons bonded together, the cross sectional area of the various hexagons forming said core being small so as to impart rigidity and strength to said building panel, said web being provided on its unbonded, exposed areas with an after-coating of a non-toxic, mineral hydraulic cementitious material whereby said core will be highly flame resistant and will have added stiffness, said facing element being highly fire resistant and being a rigid board, said after-coating cementitious material being applied to the inner face of said facing element, and said after-coating on the ends of said core and on said facing element providing a fire resistant bond between the fire resistant core and the fire resistant facing element while leaving the honeycomb spaces between the facing elements substantially clear of any after-coating material, said building panel being provided with a relatively rigid cellular structure.

9. A method for making a reticulated web comprising immersing in a fluid mineral hydraulic cementitious substance undulating sheet material of paper which is substantially free of resin and sizing substances, coating all exposed surfaces of the paper sheet material, drying said fluid coated cementitious substance whereby when thoroughly dried and set a strong, rigid and lightweight web will be formed.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Barnhart Sept. 30, 1913 Borsodi Apr. 15, 1930 Thomson Jan. 9, 1934 Price Apr. 30, 1940 Davis Sept. 25, 1945 May Oct. 14, 1947 10 Rapp Feb. 1, 1949 Clements June 13, 1950 Delmar et a1. Aug. 26, 1952 Pajak Sept. 2, 1952 Bell Feb. 23, 1954 FOREIGN PATENTS Gleat Britain Apr. 23, 1935 Great Britain May 29, 1946 Great Britain Nov. 30, 1948 

1. A RETICULATED WEB OF PAPER HAVING WALL PORTIONS DEFINING CELLULAR VOIDS OPEN AT OPPOSITE SIDES OF THE WEB AND HIGHLY FLAME-RESISTANT MINERAL HYDRAULIC CEMTITIOUS MATERIAL COVERING SUBSTANTIALLY ALL SURFACES AND EDGES OF THE RETICULATED WEB AND PROVIDING A RELATIVELY RIGID COATING HAVING SUBSTANTIAL THICKNESS OVER SUBSTANTIALLY ALL SURFACES AND EDGES OF THE RETICULATED WEB, THEREBY TO PROVIDE A RELATIVELY RIGID CELLULAR STRUCTURE WHICH IS SUBSTANTIALLY PROOF AGAINST HEAT AND FLAME. 